The present invention relates to a method for producing a mixture including an injected engine fuel, a combustion engine intake-air and an evaporative gas from the engine fuel.
In a conventional method for measuring a characteristic of a mixed gas, as disclosed by Publication of Japanese Laid-open Patent Application Shou-63-219863, an amount of an evaporative fuel emission contained in a charcoal canister is assumed, and a duty ratio of an electromagnetic valve in a discharge path of the evaporative fuel emission is controlled according to the assumed amount so that a flow rate of the evaporative fuel emission into an engine intake-air is adjusted. Further, Publication of Japanese Laid-open Patent Application Shou-62-20669 discloses an apparatus for preventing an evaporative fuel emission from being discharged to the atmosphere, comprising an operational condition detecting device in which an operational condition of an internal combustion engine is detected by measuring an intake-air flow rate, an opening degree of a throttle valve, a content of oxygen remaining in an exhaust gas and so forth, and an adjusting device by which an opening degree of an evaporative fuel emission path is adjusted according to the detected operational condition of the internal combustion engine.